When I point out that I don't vote, I'm often told, "What if everybody thought that way?" Presumably, the answer is that elections wouldn't work. democracy would fail, and we'd end up with a president that nobody likes.
The good news is that our choices aren't between everybody thinking that way and nobody thinking that way. What if only some people thought that way?
Consider, what if everybody got in an elevator at the same time? We'd all be crushed! So what does a reasonable person do? They look in the elevator to make sure that everyone else isn't there. If they are, they don't get in. Now what if everyone looked into the elevator to make sure everyone else isn't there? Well, the first people would see the empty elevator and get in. This would continue until the elevator is full, and then the next person wouldn't get in.
Kind of like looking in the elevator, what if people made a reasonable prediction about how many other people are going to vote in the election? 150 million? Nah, I won't vote this time. 10? Sure I'll vote. If everyone does this the number of voters radically decreases without hitting zero. It decreases to the point where the next vote has an unreasonable chance of effecting outcomes, but the last vote had a reasonable chance of effecting outcomes. If people did that, like I do, we'd spare ourselves from wasting a lot of time.